What is the essential difference between TPEP anti-corrosion steel pipe and 3-layer PE anti-corrosion steel pipe in anti-corrosion spiral welded steel pipe? TPEP anti-corrosion steel pipe, also known as outer 3-layer PE inner epoxy anti-corrosion steel pipe, can be seen from the name that TPEP anti-corrosion steel pipe includes 3-layer PE anti-corrosion. That's right, if we only look at the external anti-corrosion form of TPEP anti-corrosion steel pipes, we can also call them 3-layer PE anti-corrosion steel pipes